Not P but Moby-Dick (107)

[Mike Jing]

>From Chapter 133:

As now he thus vainly strove, the jaw slipped from him; the frail gunwales
bent in, collapsed, and snapped, as both jaws, like an enormous shears,
sliding further aft, bit the craft completely in twain, and locked
themselves fast again in the sea, midway between the two floating wrecks.
These floated aside, the broken ends drooping, the crew at the stern-wreck
clinging to the gunwales, and striving to hold fast to the oars to lash
them across.

What does "lash them across" mean here? Are they trying to fasten the oars
across the gunwales so it's easier to hold on to the wreck?

This also appeared in Chapter 48, when the boat was not actually wrecked:

Though completely swamped, the boat was nearly unharmed. Swimming round it
we picked up the floating oars, and lashing them across the gunwale,
tumbled back to our places. There we sat up to our knees in the sea, the
water covering every rib and plank, so that to our downward gazing eyes the
suspended craft seemed a coral boat grown up to us from the bottom of the
ocean. . . . . . . The oars were useless as propellers, performing now the
office of life-preservers.